Project Summary Modern advancements in military trauma care have resulted in an unprecedented era of combat injured survivors. Over 50,000 service members have been wounded in action in the past 15 years and, for the first time in history, many are able to live with serious injuries that were previously considered fatal. Yet, little is understood about the short- and long-term physical and mental health symptom trajectories of these injuries. Understanding the clinical presentations and symptom trajectories in this severely injured cohort is paramount for nursing science to develop and test interventions and maximize recovery across military, veteran, and traumatically injured civilian populations. This proposed research-intensive training application prepares the applicant to conduct a secondary analysis of data from the recently completed prospective and not yet published longitudinal Regional Anesthesia Military Battlefield Pain Outcomes Study (RAMBPOS) (VA RRD D45064-1). The purpose of RAMBPOS was to examine the short- and long-term benefits of implementing early regional anesthesia techniques for pain control after a major traumatic injury to one or more extremities during combat in the Iraq and Afghanistan conflicts. This is the largest and most comprehensive dataset of combat injured patient reported outcomes and includes longitudinal data on over 300 service members? short- and long-term pain and mental health outcomes. This secondary analysis will address the key question: in an era of unprecedented survival after complex and life-threatening injuries, what are the short- and long-term symptom trajectories of post-traumatic stress disorder (PTSD) based on initial pain severity presentations, even after exposure to pain management interventions, specifically regional anesthesia (RA)? Furthermore, this investigation will evaluate the cost-effectiveness of RA, a potential Certified Registered Nurse Anesthetist (CRNA) led intervention. The proposed study will further trauma providers? understanding of the complex relationship between pain severity, commonly referred to as the 5th vital sign of nursing care, and PTSD symptom severity in the context of the combat injury phenomena. The findings of this study are relevant not only to military and veteran trauma care, but also to civilians experiencing complex and multisystem injuries. The results of this study will address the National Institute of Nursing Research?s mission of advancing symptom and pain science. This line of inquiry provides foundational training for the applicant to develop a research career committed to improving the quality of life of all seriously injured persons.